Visible light-driven decomposition of α-pinene and toluene over N and Fe dual-doped one-dimensional titania nanostructures with improved efficiency

This study explores the photocatalytic performance of novel N and Fe dual-doped, one-dimensional TiO₂ nanotube structures (N–Fe–TNTs) for the degradation of α-pinene and toluene under visible-light illumination. N–Fe–TNTs were synthesized using a combination of sonochemical-hydrothermal-impregnation processes. N–Fe–TNT hybrids showed higher photocatalytic efficiency compared to pure TNT, N-doped TNT, and Fe-doped TNT. Specifically, the average decomposition efficiencies for α-pinene and toluene over N–Fe–TNT-1.0 were 94.6% and 88.7%, respectively. Moreover, the photocatalytic efficiency of the N–Fe–TNT hybrids improved as the Fe loading was increased gradually from 0.35% to 1.0%, though a further increase in Fe loadings led to reduced photocatalytic efficiency. The mineralization efficiencies of α-pinene and toluene were 43.2% and 47.7%, respectively. Gaseous intermediates were determined during the photocatalytic processes. Overall, the synthesized N–Fe–TNTs could be used efficiently to decompose α-pinene and toluene under visible-light exposure.